Pagels’ lucid history of the social construction of Satan is not only a wealth of historical information, but also a source of important insights into the demonization of “intimate enemies” that has marked the history of Christianity. Pagels writes that she began with the assumption that Christian discourse about invisible beings, including Satan and other angels, had as its primary purpose what Austrian-born Israeli philosopher Martin Buber called the “moralizing” of the natural universe. She discovered that it had far more to do with social relations among particular persons, and that discovery informs the entire book. She traces the development of Satan in the Jewish community from a sort of roving agent acting on God’s behalf–always obstructing but not always evil–to an increasingly evil force identified more and more with intimate enemies, members of one’s own community with whom one is in conflict. That trend toward demonization of portions of the Jewish community intensified with the emergence of Christianity and became the basis for demonization of heretics and centuries of anti-Semitism. This is an informative, beautifully written book, an excellent illustration of how careful historical research can illuminate questions of more than passing historical interest.